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-rw-r--r--src/zip.cr353
1 files changed, 325 insertions, 28 deletions
diff --git a/src/zip.cr b/src/zip.cr
index 4761695..0dcc7ec 100644
--- a/src/zip.cr
+++ b/src/zip.cr
@@ -180,30 +180,6 @@ module Zip
end
end
- # TODO
- class Reader
- getter? :closed, :sync_close
-
- def initialize(
- @io : IO,
- @pos : UInt32 = 0,
- @sync_close : Bool = false,
- )
- @closed = false
- end
-
- private def assert_open
- raise Error.new("already closed") if closed?
- end
-
- def close
- assert_open
-
- @io.close if @sync_close
- @closed = true
- end
- end
-
module NoneCompressionHelper
def compress_none(src_io, dst_io)
crc = 0_u32
@@ -739,15 +715,328 @@ module Zip
end
end
+ # alias Source = IO::FileDescriptor | MemoryIO
+
+ class Source
+ include IO
+
+ def initialize(@io : IO::FileDescriptor | MemoryIO)
+ end
+
+ delegate read, to: @io
+ delegate write, to: @io
+ forward_missing_to @io
+ end
+
+ # central file header signature 4 bytes (0x02014b50)
+ # version made by 2 bytes
+ # version needed to extract 2 bytes
+ # general purpose bit flag 2 bytes
+ # compression method 2 bytes
+ # last mod file time 2 bytes
+ # last mod file date 2 bytes
+ # crc-32 4 bytes
+ # compressed size 4 bytes
+ # uncompressed size 4 bytes
+ # file name length 2 bytes
+ # extra field length 2 bytes
+ # file comment length 2 bytes
+ # disk number start 2 bytes
+ # internal file attributes 2 bytes
+ # external file attributes 4 bytes
+ # relative offset of local header 4 bytes
+ #
+ # file name (variable size)
+ # extra field (variable size)
+ # file comment (variable size)
+
+ class Entry
+ getter :version, :version_needed, :flags, :method, :datetime, :crc,
+ :compressed_size, :uncompressed_size, :path, :extras,
+ :comment, :internal_attr, :external_attr, :pos
+
+ def initialize(io)
+ # allocate slice for data
+ mem = Bytes.new(46)
+
+ # read entry
+ if ((len = io.read(mem)) != 46)
+ raise Error.new("couldn't read full CDR entry (#{len} != 46)")
+ end
+
+ # create memory io for slice
+ mem_io = MemoryIO.new(mem, false)
+
+ magic = UInt32.from_io(mem_io, LE)
+ if magic != MAGIC[:cdr_header]
+ raise Error.new("invalid CDR header magic")
+ end
+
+ # read versions
+ @version = UInt16.from_io(mem_io, LE).as(UInt16)
+ @version_needed = UInt16.from_io(mem_io, LE).as(UInt16)
+
+ # TODO: check versions
+
+ # read flags, method, and date
+ @flags = UInt16.from_io(mem_io, LE).as(UInt16)
+ @method = UInt16.from_io(mem_io, LE).as(UInt16)
+ @datetime = UInt32.from_io(mem_io, LE).as(UInt32)
+
+ @crc = UInt32.from_io(mem_io, LE).as(UInt32)
+ @compressed_size = UInt32.from_io(mem_io, LE).as(UInt32)
+ @uncompressed_size = UInt32.from_io(mem_io, LE).as(UInt32)
+
+ # read lengths
+ @path_len = UInt16.from_io(mem_io, LE).not_nil!.as(UInt16)
+ @extras_len = UInt16.from_io(mem_io, LE).as(UInt16)
+ @comment_len = UInt16.from_io(mem_io, LE).as(UInt16)
+
+ @internal_attr = UInt16.from_io(mem_io, LE).as(UInt16)
+ @external_attr = UInt32.from_io(mem_io, LE).as(UInt32)
+ @pos = UInt32.from_io(mem_io, LE).as(UInt32)
+
+ # close memory io
+ mem_io.close
+
+ # read path
+ @path = if @path_len > 0
+ buf = Bytes.new(@path_len)
+
+ if io.read(buf) != @path_len
+ raise Error.new("couldn't read CDR entry name")
+ end
+
+ # TODO: handle encoding
+ String.new(buf)
+ else
+ ""
+ end
+
+ # read extras
+ @extras = if @extras_len > 0
+ buf = Bytes.new(@extras_len)
+
+ if io.read(buf) != @extras_len
+ raise Error.new("couldn't read CDR entry extras")
+ end
+
+ # TODO: decode extras?
+ buf
+ else
+ # TODO
+ Bytes.new(0)
+ end
+
+ # read comment
+ @comment = if @comment_len > 0
+ buf = Bytes.new(@comment_len)
+ if io.read(buf) != @comment_len
+ raise Error.new("couldn't read CDR entry comment")
+ end
+
+ # TODO: handle encoding
+ String.new(buf)
+ else
+ ""
+ end
+ end
+ end
+
+ # 4.3.16 End of central directory record:
+ #
+ # * end of central dir signature 4 bytes (0x06054b50)
+ # * number of this disk 2 bytes
+ # * number of the disk with the
+ # start of the central directory 2 bytes
+ # * total number of entries in the
+ # central directory on this disk 2 bytes
+ # * total number of entries in
+ # the central directory 2 bytes
+ # * size of the central directory 4 bytes
+ # * offset of start of central
+ # directory with respect to
+ # the starting disk number 4 bytes
+ # * .ZIP file comment length 2 bytes
+ # * .ZIP file comment (variable size)
+
+ class Archive
+ getter :entries
+
+ def initialize(@io : Source)
+ # initialize entries
+ # find footer and end of io
+ footer_pos, end_pos = find_footer_and_eof(@io)
+
+ # skip magic
+ @io.pos = footer_pos + 4
+
+ # create slice and memory io
+ mem = Bytes.new(18)
+
+ # read footer into memory io
+ @io.pos = footer_pos + 4
+ if ((len = @io.read(mem)) < mem.size)
+ raise Error.new("couldn't read zip footer")
+ end
+
+ # create memory io for slice
+ mem_io = MemoryIO.new(mem, false)
+
+ # read disk numbers
+ @disk_num = mem_io.read_bytes(UInt16, LE).as(UInt16)
+ @cdr_disk = mem_io.read_bytes(UInt16, LE).as(UInt16)
+
+ # check disk numbers
+ if @disk_num != @cdr_disk
+ raise Error.new("multi-disk archives not supported")
+ end
+
+ # read entry counts
+ @num_disk_entries = mem_io.read_bytes(UInt16, LE).as(UInt16)
+ @num_entries = mem_io.read_bytes(UInt16, LE).not_nil!.as(UInt16)
+
+ # check entry counts
+ if @num_disk_entries != @num_entries
+ raise Error.new("multi-disk archives not supported")
+ end
+
+ # read cdr position and length
+ @cdr_len = mem_io.read_bytes(UInt32, LE).not_nil!.as(UInt32)
+ @cdr_pos = mem_io.read_bytes(UInt32, LE).not_nil!.as(UInt32)
+
+ # check cdr position
+ if @cdr_pos.not_nil! + @cdr_len.not_nil! >= end_pos
+ raise Error.new("invalid CDR offset: #{@cdr_pos}")
+ end
+
+ # read comment length and comment body
+ @comment_len = mem_io.read_bytes(UInt16, LE).not_nil!.as(UInt16)
+ @comment = if @comment_len.not_nil! > 0
+ # allocate space for comment
+ slice = Bytes.new(@comment_len.not_nil!)
+
+ # seek to comment position
+ @io.pos = footer_pos + 22
+
+ # read comment data
+ if ((len = @io.read(slice)) != @comment_len)
+ raise Error.new("archive comment read truncated")
+ end
+
+ # FIXME: shouldn't assume UTF-8 here
+ String.new(slice, "UTF-8")
+ else
+ ""
+ end
+
+ # close memory io
+ mem_io.close
+
+ # read entries
+ @entries = [] of Entry
+ read_entries(@entries, @io, @cdr_pos, @cdr_len, @num_entries)
+ end
+
+ private def read_entries(
+ entries : Array(Entry),
+ io : Source,
+ cdr_pos : UInt32,
+ cdr_len : UInt32,
+ num_entries : UInt16,
+ )
+ # get end position
+ end_cdr_pos = cdr_pos + cdr_len
+
+ # seek to start of entries
+ io.pos = cdr_pos
+
+ # read entries
+ num_entries.times do
+ # create new entry
+ entries << Entry.new(io)
+
+ # check position
+ if io.pos > end_cdr_pos
+ raise Error.new("read past CDR")
+ end
+ end
+ end
+
+ private def find_footer_and_eof(io : Source)
+ # seek to end of file
+ io.seek(0, IO::Seek::End)
+ end_pos = io.pos
+
+ if end_pos < 22
+ raise Error.new("too small for end of central directory")
+ end
+
+ curr_pos = end_pos - 22
+ while curr_pos >= 0
+ # seek to current position
+ io.pos = curr_pos
+
+ # read what might be the end_cdr magic
+ maybe_end_magic = UInt32.from_io(io, LE)
+
+ if maybe_end_magic == MAGIC[:cdr_footer]
+ # jump to archive commment len (maybe)
+ maybe_comment_len_pos = curr_pos + 20
+ io.pos = maybe_comment_len_pos
+
+ # get archive commment len (maybe)
+ maybe_comment_len = UInt16.from_io(io, LE)
+
+ if curr_pos + 22 + maybe_comment_len == end_pos
+ # magic and comment line up: probably found end_cdr
+ return { curr_pos, end_pos }
+ end
+ end
+
+ # step back one byte
+ curr_pos -= 1
+ end
+
+ # throw error
+ raise Error.new("couldn't find end of central directory")
+ end
+ end
+
+ class Reader
+ getter? :closed, :sync_close
+ getter :zip
+
+ def initialize(
+ @io : Source,
+ @pos : UInt32 = 0_u32,
+ @sync_close : Bool = false,
+ )
+ @closed = false
+ @zip = Archive.new(@io)
+ end
+
+ private def assert_open
+ raise Error.new("already closed") if closed?
+ end
+
+ def close
+ assert_open
+
+ @io.close if @sync_close
+ @closed = true
+ end
+ end
+
def self.read(
io : IO,
pos : UInt32 = 0_u32,
sync_close : Bool = false,
- &cb : Reader -> \
+ &cb : Archive -> \
)
begin
- r = Reader.new(io, pos, sync_close)
- cb.call(r)
+ r = Reader.new(Source.new(io), pos, sync_close)
+ cb.call(r.zip)
ensure
if r
r.close unless r.closed?
@@ -758,8 +1047,16 @@ module Zip
end
def self.read(
+ slice : Bytes,
+ &cb : Archive -> \
+ )
+ src = Source.new(MemoryIO.new(slice, false))
+ read(src, 0_u32, false, &cb)
+ end
+
+ def self.read(
path : String,
- &cb : Reader -> \
+ &cb : Archive -> \
)
File.open(path, "rb") do |io|
read(io, 0_u32, true, &cb)